1. Field of the Invention
The present invention relates to a navigation system for guiding a vehicle to a destination via a predetermined route and, more particularly, to a navigation system for enabling a detailed map of the route, showing roads and branching points on the route, for example that portion of the route in the vicinity of the destination and the guidance ending location, to be accessed from a route information screen.
2. Related Art
The prior art navigation system gives guidance along a route so that the vehicle can safely arrive at a first destination. In recent years, efforts have been vigorously pursued to improve performances, such as navigation accuracy, operability and visibility. The prior art navigation system is typically provided with a destination setting screen to be used for setting the route, a route searching screen for displaying the searched route, a route information screen for displaying the searched route information, and a route guiding screen to be opened for guidance automatically or according to the will of the driver. The display screen, after the guidance has started, may include a wide area map for guidance over a wide area of the route, a set of several section maps including that section of the entire route which is being followed, and an intersection map for guiding at intersections.
Some navigation systems further function to provide information of the remaining distance, the name of the intersection, the direction in which the vehicle should turn, to teach distinguishing landmarks so as to confirm the route being followed, and to provide guidance, not only through visual display, but also audibly.
In order to set a route in such a navigation system, it is necessary to input a starting point and a destination. If the starting point and the destination are determined by the inputting, route searching is processed from the vicinities of the departing point and the destination and the route information data between them so that an optimum route is determined from among a plurality of possible routes. When this route search is ended, there is opened an entire route map which is displayed with the present position, the destination and the route in between. The route guidance is started by teaching the summary of the route using that entire route map.
In some of the navigation systems having such route guiding functions, the names of the entrance and exit of an expressway to be used at first are exclusively displayed, as the essential points of the route, after the route search has been ended, as proposed by us in Japanese Patent Application No. 220111/1992. As disclosed in Japanese Patent Laid-Open No. 4285/1990, on the other hand, peripheral maps are displayed by a single-action scrolling or by switching the scale of the map.
In the route guide systems of the prior art, however, when it is desired to know in advance detailed route information, in the form of a summary of the roads and branching points on the route, or the route direction or configurations of the branching points or the essential points on the route, or the routes in the vicinity of the destination or the guide ending location, or when information for the route in the front of the present position is desired during the guidance, the route is searched by switching the map scale or by the single-action scrolling operation from the screen after the route guidance has started. These operations are not easy and are time-consuming.